Gravel grading device



March 6, J. M N JR 2,370,717

- GRAVEL GRADING DEVICE Filed March 22, 1943 V INVEN TOR.

JUL/05 5. CHP/STMII/ZL/Q.

cQm/LWW Patented Mar. 6, 1945 UNITED STATES PATENT OFFICE. GRAVELiZEIEG DEVICE Julius B. Christman, Jr., Clay Township,'St.

Jose'ph County, Ind.

I Application March 22, 1943, SerialNo. 479,985

3 Claims. ((31. 209-313) This invention relates to gravel grading devices. More particularly, the invention relates to a device for eliminating fiat shale and fiat stones from gravel. I v

Certain deposits of gravel contain a substantial quantity of fiat shale. This material is soft and its inclusion in gravel in any substantial percentage is objectionable. Consequently, spec'- ifications for gravel frequently limit-the amount of flat shale which acceptable gravel may contain. To'meet such specifications, it is neces sary for those producing gravel from deposits containing excessive quantities of the soft shale to grade or sort the gravel to extract the shale therefrom. This has required manual grading or sorting heretofore, as by-the employment of "Fig-4 is a fragmentary detail sectional view taken on line 4 4 of Fig. 3. i

hand pickers who pick out the shale as the gravel character having a vibrating, member along which gravel is adapted to travel in a predetermined direction and including at least a portionformed from a plurality of elongated rigidmembers extending in the direction of travel of the gravel and spaced apart a-distance less than the diameter of the round hard stones fedtheretoand greater than the thickness of fiat components.

A further object is to provide a device of this character having a plurality of fixedly'interconnected spaced. parallel bars adapted to be vibrated, the adjacent faces of said bars converg' ing toward the bottom thereof.

A further object is to provide a device of this character including a rigid unit adapted to ;be vibrated andformed from a pluralityof spaced parallel elongated angle irons having their apices upwardly directed and spaced apart a distance greater than the average diameter of the flat pieces, the spacing between said angle irons being less than the average diameter of the fiat pieces and greater than the thickness thereof.

Other objects will be apparent from the description and appended claims. 1

In the drawing:

Fig. l is a top plan view of the device.

Fig. 2 is a side view of the, device with parts broken away. a V

Fig. 3 is a fragmentary vertical transverse sectional view takenonline 3-3 of Fig. 1..

Fig. 5 is a fragmentary vertical sectional view taken on line 3-3 of Fig. l, butlooking in a disimilar to Fig. 6, of a modified construction.

' Referring to the drawing, which illustrates one embodiment of the invention as applied to a gravel separator or grader ofv the inclined screen type,"numeral l0 designatesfthe legs of arigid frame which includes side rails l l and cross bars l2. Rails ll'each mount a bearing 13 intermediate the length thereof. A shaft [4 is journaled in bearings l3, and has an eccentric portion 15 (Fig. 7)intermediate said'bearings. Shaft 44 is rotated in any conventional manner.

A vibrating unit is mounted within the frame. The vibrating unit includes a pair of spaced parallel elo'ngated'vertical side plates l6 which are preferably-longitudinally inclined or tilted.

The plates 16 are fixedly interconnected by cross members, including a tubular member I! positioned intermediate the ends thereof and adjacent the upper edge thereof. Tubular member mounts a plurality of eccentric bearings, best illustrated in Fig. '7. These bearings preferably include an outer annular race 18, an inner race [9, and bearing members 20. The bearings serve to journal the eccentric portion l5 of shaft 14, and one of said races,here illustrated asthe inner race l9 has eccentric inner and outer pe- 1 eccentric shaft portionis small, and-the amplitude of the resultant movement of the vibrating unit is only a fraction of. an inch, for example each end of each of the side plateslfi. .Bracket 2| includes a vertical cylindrical portion 22 inter- I sected by a horizontal divider memberv 23, to provide a pair of alignedcup-shaped members-to receive the adjacent ends of a pair of cylindrical resilient members 24, such as cylindrical blocks of rubber. Each frame leg fixedly mounts, in vertically spaced relation, 2. pair of brackets 25 which include facing aligned cup-shaped portions 26 receiving and supporting the lower end of the lower resilient member 24 and fitting over the upper end of the upper resilient member 24, respectively. Resilient members 24 yield to accommodate the movement imparted to the vibrating unit by shaft eccentric l5, thereby providing a resilient mounting for the vibrating unit maintaining it at desired inclination at all times.

An elongated inclined gravel supporting member, here illustrated as a screen 21 of any suitable mesh, spans and is fixedly secured to the side plates l6. Screen 21 is preferably positioned sub-. stantially parallel to the top and bottom edges of plates [6 and is secured thereto adjacent the bottom edges thereof. Screen 21 preferably extends from the elevated end of thevibrating unit'to an intermediate portion i'thereof, and its lower or inner end is preferably supported upon across bar 28 secured to plates l6 at its ends. Bar 28 is preferablyof Z shape or section having a center web 29 and a lower web 30 perpendicular to web 29. A second rigid cross bar 3| is secured to plates 15 at its ends in spaced parallel relation to bar 28 in a position substantially in the inclined plane of screen Z'I'and adjacent the depressed end of the vibrating unit. Bar 3| is also preferably of Z section, but its center web 32 is preferably narrower than web 29 of bar 28 as illustrated. A second inclined gravel, supporting section or screen 33 mayispan and be secured to the side plates l5 and to the bar 3| and extend to the depressed end, of the vibrating unit. Screen section 33 is preferably secured to the bottom face of flange 34 of bar 3| for purposes to be set out hereinafter. v

A plurality of spaced, parallel, elongated, rigid members 35 such as angle irons, are secured at their opposite. ends to bars 28 and 3|. Adjacent members 35 have downwardly diverging opposite side walls, such as the flanges 36 of inverted angle bars, whereby troughs, grooves or guideways are provided therebetween, the same being open or longitudinally slotted at their bases. The elevated ends of members 35 bear against the center Web 29 of bar 28, and the upper edges of said members 35 lie at or belowthe level of the top of bar 28,whereby no obstacle interferes with free movement of gravel from screen 21 onto membe1's'35. The upper edges of members 35 at the opposite ends thereof project substantially above the level of the flange 34 of bar 3| whereby round hard stones 31 of a size to travel over screen 21 without falling therethrough may roll freely from the grooves between members .35 and onto screen 33 without interference from bar 3|.

The spacing between adjacent members 35 is slightly greater than the average or maximum thickness of the fiat pieces encountered in a particular gravel deposit, and less than the size of the mesh openings in screen 21. Thus soft shale is commonly found in thicknesses ranging up to inch and in diameters or dimensions exceeding /4 inch. For shale of this size, the spacing of members 35 should be approximately threeeighths inch. Assuming the mesh openings of screen 21 to be five-eighths or three-fourths inch, soft fiat shale will travel thereover andonto the members 35 when the screen is vibrated, and can drop or pass between members 35 if positioned edgewise.- The spacing between-the apices or the angle irons 35 is preferably greater than the average diameter of the flat shale, for example from 2" to 3" or even more. Thus shale discharged from screen 2'! falls into the guideways between members 35. Vibration of members 35 tends to tilt the shale 38 into the plane of one of the inclined side walls 36 of the guideway, as illustrated in Fig. 3, whereupon it is free to slideedgewise through the space between members 35. In order to insure passage of shale 38 into the guideways between members 35, said members should be substantially of inverted V shape or cross section, whereby the top surfaces of said members are of limited area or extent which prevents the shale from balancing or resting flatwise thereon and which results in tipping and sliding of the shale into one of the guideways at each side of each member when the shale strikes the upper edge of one of the members 35. Hence the soft flat shale is automatically discarded or ejected from the gravel batch, while the round hard stones traverse the guideways between members 35 and the lower screen section 33 for discharge at the selected point.

A conveyor 39, such as a belt trained around and supported by a plurality of pulleys or rollers 40, or a chute or other discharging means, ex-

tends below members 35 to receive the ejected flat material and convey it to a discharge point. Other conveyors, chutes, etc., may be associated with the device beneath the respective screens and at the discharge end of the device to carry away the screened sand and small stones and the graded gravel, as is well understood in the art.

A slightly modified construction of the lower end of the flat-element-rejecting unit is shown in Fig. 9. The transverse bar at the lower end of said unit'is preferably bent transversely thereof to provide a portion M to which members 35 are fixedly secured and which are positioned thereupon, and a forwardly downwardly inclined portion 42 extending at an acute angle to members 35. Thus, if a tapered stone 43, having a portion 44 of a thickness too great to pass between members 35 and a portion thin enough to pass therebetween, becomes lodged between said members; it will slide between members 35 until it reaches portion 42' and will then ride thereon as shown in dotted lines for discharge from the unit. This prevents clogging of the device.

While the device has been illustrated and described as constituting a part of an inclined vibrating gravel screening unit, it may be a separate entity or may be incorporated in other types of vibrating equipment. Likewise, while the inclined position of the device is preferred, it may be horizontal if constructed to cause gravel and stone to travel in a generally longitudinal direction while being vibrated.

' I claim:

1. In a gravel grading device, a vibratory tray comprising a pair of rigidly connected opposite side walls, a pair of supports spanning and carried by said Walls, a plurality of similar uniform angle bars supported at their ends by said bars in inverted, parallel, spaced, longitudinally inclined position intermediate the ends of said tray, an inclined screen spanning said side walls with its lower end carried by one support at or above the level of the crests of the upper ends of said-bars, and a second inclined screen spanning said side walls with its upper end carried by the other support adjacent the level of the bottoms of the lower-ends of said bars.

2. In a gravel grading device, a vibratory tray comprising a pair of rigidly connected opposite side walls, a pair of Z-bars spanning said walls, a plurality of elongated rigid members of uniform cross section supported at their ends by the lowermost flanges of said Z-bars in spaced parallel inclined position, the upper Z-bar having a web portion of a width substantially equal to the vertical cross sectional dimension of said elongated members and the other Z-bar having a comparatively narrow webgportion, and-upper and lower inclined screensspanning said tray and supported at their inner ends by the uppermost flanges oi the Z-bars adjacent thereto.

3. In a gravel grading device, a tray comprising a pair of rigidly connected opposite side walls,

a pair of cross bars spanning said side walls, a pair of inclined screens spanning said side wall I and supported at their inner ends by said bars, and a plurality of rigid longitudinalbars secured at their ends to said cross bars in spaced parallel inclined position, at least the upper cross adjacent ends of said longitudinal bars.

JULIUS B. CHRISTMAN, JR. 

